This takes place directly after episode 9x13 'The Purge', but Cas is still an angel.

Sam walked out of the room leaving his brother hollow. Dean downed the last of the Scotch in his glass and called out to his friend.

"Cas?" He croaked, his voice uncharacteristically weak. "Could you please come here? I need to talk." With a whoosh of wings, Dean's favorite angel appeared a few feet away. With one glance, Cas sensed something was wrong.

"What is it, Dean?"

"Sam..." He paused to take a deep breath. "Sam told me he wouldn't have saved me if I was in his position. He said he couldn't trust me and that I hurt more than I help." The words came out too rushed, as though they had been begging Dean to release them from the cage that is his mind.

Cas took a step forward and allowed Dean to continue.

"All my life I've been told to protect Sammy. I've only ever wanted a better life for him. I even let him leave and go off to college to try to get out of hunting." Dean scoffed at himself and shook his head.

"But now after what he said, it's like he doesn't care about me anymore. Or maybe he never really did. I don't know. What I do know is the the psychiatrist was wrong; Sam and I are't co-dependent, I'm just dependent."

Dean practically spit the last word out. There were tears streaming down his face now. He was too angry, too guilty, too hateful.

He suffocated the glass still in his hand and it broke easily. Blood ran down his arm as Cas grasped his wrist.

"Let go, Dean," Cas commanded softly. Dean looked at his friend and his fingers slowly opened, causing the glass to fall to the floor and shatter. He stalked past Cas and headed toward the garage with one thought on his mind: an end.

However, Cas was quicker, and he appeared directly in front of Dean causing the crumbling man to abruptly stop.

"Dean, don't."

With two words the last of Dean's composure shattered. He fell into Cas; the angel easily supporting the hunter. Dean rested his head in the crook of Cas' neck and whispered so low that Cas had to strain to hear him.

"Do you know what it feels like when no one loves you?"

Castiel had witnessed empires burn, held his brothers' broken and lifeless bodies on the battlefield, and watched people beg for Death to take them, but Dean Winchester's face in that moment was the most heart-wrenching thing he had ever seen. He could not just stand here and watch Dean castigate himself.

"Dean, even if what you said is true and your brother doesn't care about you, which I highly doubt, I care about you."

Dean looked up from his place against Cas' neck with tears on his checks and smiled sadly.

"Cas, you wouldn't miss me if I was gone. I'm just the blink of an eye to you. You're thousands of years old. You wouldn't care if one human died."

Cas stared back at Dean with disappointment and pity.

"Dean...I love you. You are not the blink of an eye to me, and you are are not just 'one human'. You are Dean Winchester. You have saved so many and lost so much."

Cas folded his arms around the hunter and—though unnoticed—enveloped his wings around the two of them as well.

"We should get you to bed."

Though Dean didn't speak, he nodded his head, giving the angel permission to fly them both to Dean's room.

Once Cas had gotten Dean in his bed, he turned to leave, only to find a hand capture the sleeve of his trench coat.

"Don't go."

Cas wordlessly opened the nest of blankets that he had gingerly placed there only moments before. Laying next to his hunter, he felt serene. Though Castiel knows he will not sleep, he is content with just...being. A tentative voice brushes away his train of thought.

"Cas?"

"Yes, Dean?"

"I love you, too."